1. Field of the Invention
This invention relates to a method for bonding substrates and an apparatus for bonding substrates, and a method for irradiating a particle beam and an apparatus for the irradiation which can be utilized therefor. Particularly, the method for bonding substrates and the apparatus for bonding substrates according to this invention are adapted to irradiate a plurality of kinds of particle beams with the object of exalting the strength of bonding substrates. The method for irradiation and the apparatus for irradiation according to this invention are adapted to effect the irradiation of the plurality of kinds of particles beams by the use of one device.
2. Description of Related Art
As a technique for mutually bonding such substrates as semiconductor substrates, the technique which is called “plasma assist bonding” has been attracting attention. For example, the technique which comprises irradiating the surfaces of substrates with an oxygen plasma (O+ plasma), causing the oxygen plasma to react with the water component in the atmosphere thereby forming a hydroxyl group (OH group) on the surfaces of the substrates, and mutually bonding the substrates having a hydroxyl group formed thereon has been known to the art.
U.S. Pat. No. 6,180,496 discloses a technique for bonding substrates by bringing into mutual contact the surfaces thereof which have been irradiated with a plasma in a chamber having a bonding apparatus mounted thereon.
Such conventional techniques for bonding substrates as described above, however, have never embraced a contrivance directed toward exalting the strength of bonding substrates by the irradiation of a plurality of kinds of particle beams as by irradiating an oxygen plasma and a nitrogen radical in combination. The conventional techniques for bonding substrates, therefore, have possibly encountered difficulty in exalting the strength of bonding substrates fully satisfactorily. A simple and convenient method of irradiation which is capable of effecting plasma radiation and radical radiation by the use of one device has never been proposed to date.